Our research focuses on cooperation between institutions in the implementation of their policies in the regions. This issue is of particular importance in a particular economic context of financial crises and excessive state indebtedness, where efforts are made to control the allocation of public funds while at the same time increasing the effectiveness of public action: this is a difficult equation for public decision-makers. While the idea of “drastic cuts” in public spending is necessary for some, we show that previously under-exploited performance opportunities exist, based on the capacity of actors in the region to work better together, including the institutions. An institution does not usually have a unique role in implementing a policy in a territory. Other institutions are working on the same or related fields. They work either in their corner, sometimes in duplicate, or in consultation and coordination to make them more effective: it is in the latter case that we will speak of effective interinstitutional cooperation. The institutions also work with relay actors to multiply their capacity to achieve their objectives. In a given territory the institutions often rely on the same relays. Their ability to coordinate with each other depends on their ability to coordinate the relays effectively and to ensure that their action is in line with the expected performance. Performance is based in particular on the ability of the relays to support the implementation of territorial strategies for the targeted populations: socio-economic groups, businesses, local authorities, etc. Thus, the institutions wish to influence the support skills of their relays. In practice, stakeholders in the region find it difficult to work together, especially the institutions, as we develop in this paper.